Junctions, such as PN junctions can be used in various devices such as diodes and transistors. PN junctions have a p-doped region of a semiconductor adjacent to an n-doped region of a semiconductor. As a diode, PN junctions can stop the flow of current in one direction while allowing flow in the opposite direction. In some transistors, two PN junctions can be used to amplify a signal.
In various embodiments, as disclosed herein GaN PN diodes can be fabricated with a vertical structure on GaN substrates, a lateral structure on insulating substrates, or in other orientations, and the PN junction in can be placed in the c-plane or in other planes.